Martha Bellisle ?and Gillian Flaccus

MOUNT VERNON, WASH.: The suspect accused of killing five people at a Macy’s department store confessed to police, court documents said, but his motive remained a mystery Monday as a portrait emerged of him as a mentally troubled young man whose parents said they were trying to help him.

Arcan Cetin, 20, appeared in court and was officially charged with five counts of first-degree premeditated murder following his arrest over the weekend for the rampage at the Cascade Mall in Burlington, north of Seattle.

Cetin appeared to express no emotion and said only “Yes, your honor” when asked by a judge if he understood his rights. Bail was set at $2 million, and his lawyer said nothing about his client in court and did not speak with reporters.

The hearing followed a terrifying weekend that began Friday night when police say Cetin stormed into the mall and killed five people, leaving Burlington residents panicked for nearly 24 hours until authorities arrested him.

Cetin, described by acquaintances as socially awkward, has a criminal record going back at least two years and one of his neighbors said he unnerved her so much that she kept a stun gun near her front door.

Cetin after his arrest admitted when interviewed by detectives he was the man captured on security video carrying a Ruger rifle inside the mall, “and he did bring the rifle into Macy’s and shot all five victims,” court documents released ahead of Monday’s hearing said.

He shot all five victims in one minute and left the rifle with a 25-round magazine on a cosmetics counter before fleeing, police said in court documents. Four died at the scene, and one died in the hospital.

The victims ranged in age from a teenage girl to a woman in her 90s.

Authorities have declined to reveal details about their investigation into the motive for the shooting, but Cetin’s stepfather David Marshall told reporters after the hearing that his stepson “has mental health issues” without elaborating.

“The only thing that we want to say at this time is that we both are totally devastated by what happened,” said Marshall, who attended the hearing with Cetin’s mother.

The court documents appeared to paint a picture of Cetin’s stepfather and mother trying to keep their son on track despite his suffering from an unspecified illness and criminal charges he faced for allegedly assaulting Marshall. Cetin came to the U.S. from Turkey and is a permanent legal resident, authorities have said.

Cetin faced charges last year for allegedly assaulting his stepfather after he caught Cetin smoking marijuana inside the house, according to court records.

He was told by a judge last December not to possess a gun but Cetin’s stepfather urged the judge not to impose a no-contact order, saying his stepson was “going through a hard time,” the records said.